High performance planar processing

6-D Laser LLC is an affiliate of leading nanometer-level motion control specialist ALIO Industries, its mission being the integration of ultrafast laser processing with precision multi-axis motion systems.

6D Laser’s central mission addresses limitations of existing laser processing systems which are largely due to sub-optimal positioning systems used by most system integrators. 6-D Laser tackles this problem by integrating ultra-fast laser material processing with the 6-D nanometer-level precision motion control solutions in which ALIO Industries specializes.

6D Laser vertically integrates all of the sub-systems required for precision laser micro-processing, and it does this by forming strategic partnerships with key component and subsystem suppliers that are required to achieve the goals of demanding precision applications.

In addition to its association with ALIO, 6-D Laser has also partnered with SCANLAB GmbH, which together with ACS Motion Control, has developed an unlimited field-of-view (UFOV) scanning solution for coordinate motion control of the galvo scanner and positioning stages called XLSCAN. 

In the area of high-performance planar processing, 6D Laser’s Unlimited Field-of-View (UFV™) solution combines the precision galvo scanning of SCANLAB’s XLSCAN system with ALIO’s precision monolithic XY stages for superior UFV™ accuracy.  As customers’ requirements of laser micro-processing applications become more demanding, the performance of legacy systems do not meet the specifications for accuracy, repeatability, and precision.

Conventional unlimited field of view systems that control a scan head and XY stage typically use the high-speed galvo scanners to compensate the slower stage’s following error. A tracking error is induced by the mass inertia and the design of each system’s servo control loop.

This means the real position of the laser spot lags the target position. Therefore, the real laser spot position is correct only after a certain amount of time – and the system momentarily oscillates. Because of this, any imperfections in the stage error mapping, or galvo field correction, will impact the overall precision due to the time lag in the servo loop cycle.

In practice, attempts are made to extrapolate the slower stage’s behavior using estimated values, but that approach only works reliably at slow speeds and for non-abrupt motions.

Especially at corners and sharp features with high acceleration or deceleration rates, this strategy can produce significant position errors.

The XL SCAN control solution used by 6D Laser applies intelligent filters to control the scan head and stages such that physical limitations of each system are taken into account prior to processing, in an integrated trajectory plan. The positions of both systems are coordinated with each other to sub-micron level precision within micro-second cycle time.

XLSCAN synchronizes the motion of the galvo scanhead and linear stages to increase the total field size without stitching or “tiling”. It has higher accuracy than competitive systems through intelligent trajectory planning. Its precision is only limited by the image field calibration and stage error mapping.

Automatic laser control can correct the spot distance relative to the velocity and the laser power across the scan field, and for increased throughput four scanheads can be controlled with a single XLSCAN controller.

In addition, the laser signal can be raised or attenuated in accordance with application requirements. This applies to straight as well as rounded laser markings, and multiple parameter changes and jumps for individual vectors are also possible.

Dr. Stephen R. Uhlhorn, CTO at 6-D Laser concludes, “Infinite Field of View (IFOV)processing systems offer considerable advantages over traditional field-stitching systems by combining the high-speed scanning of galvos with the large field sizes available with motion control stages. This increases processing speed while eliminating errors from field stitching. However, current systems are limited to processing 2D planar substrates. As manufacturing geometries continue to increase in complexity, the need to control angle of incidence (AOI) for non-planar substrates becomes crucial. 6-D Laser’s integrated IFOV laser processing system — built around ALIO’s 5-axis Laser Gimbal — solves this complex manufacturing problem.”